Typhoon Conson, known in the Philippines as Typhoon Basyang, was the second tropical cyclone during the 2010 Pacific typhoon season to impact the Philippines. Developing out of a tropical disturbance east of the Philippines on July 11, 2010, Conson quickly developed as it tracked nearly due west. Favorable environmental conditions, such as low wind shear and warm sea surface temperatures, allowed the system to intensify into a severe tropical storm by July 12. Around the same time, the JTWC assessed the storm to have been equivalent to a Category 1 hurricane. The following day, Conson struck Quezon Province with winds of 100 km/h (65 mph)[nb 1] before weakening. After crossing the archipelago, the storm entered the South China Sea where it was able to re-strengthen. By July 16, Conson attained typhoon status as it neared the southern Chinese island of Hainan. After brushing the island at peak intensity with sustained winds estimated at 130 km/h (80 mph), the storm weakened in the Gulf of Tonkin due to less favorable conditions. The storm eventually made landfall near Ha Noi, Vietnam on July 17 and dissipated the following day.

In the Philippines, Conson produced widespread, torrential rains which triggered significant flooding. At least 76 people are known to have been killed across the country and 72 others are listed as missing. Preliminary damage estimates were placed at PHP189 million (US$4.1 million). In China, at least two people have been killed due to wind-related incidents. Hainan Province sustained significant damage from the typhoon, with damage estimated at ¥500 million (US$73.8 million). Widespread damage was reported in Vietnam where at least two people were killed and 17 others were listed as missing.

Late on July 9, the Joint Typhoon Warning Center (JTWC), reported that a tropical disturbance had persisted within the vicinity of Yap island.[1] Satellite imagery showed that the disturbance had a weak circulation which was stretching over Yap with disorganized convection.[1] The disturbance was located to the south of a tropical upper tropospheric trough and was in an area of weak vertical windshear.[1] During the next day, deep convection around the disturbance increased whilst a low to mid level circulation center appeared on satellite imagery.[2] Early on July 11, the Japan Meteorological Agency (JMA) reported that the disturbance had intensified into a tropical depression, whilst the JTWC issued a tropical cyclone formation alert as the disturbance had consolidated and had multiple convective bands flowing into its low level circulation center.[3][4]

During that afternoon the JTWC reported that the disturbance had intensified into Tropical Depression 03W and initiated advisories on the system, before reporting later that day due to favorable conditions it had intensified into a tropical storm.[5][6] PAGASA also reported that afternoon that the disturbance had intensified into a depression and named it as Basyang.[7] At 0000 UTC, the next day the JMA reported that Basyang had intensified into a weak tropical storm and assigned it the name Conson and the international designation of 1002.[8] Twelve hours later, as Conson moved through favorable condition and along the southwestern edge of the subtropical ridge of high pressure, the JMA reported that the storm had rapidly intensified into a Severe Tropical Storm with windspeeds of 100 km/h (65 mph). Later that day at 1800 UTC the JTWC reported that after convection around the system had expanded and microwave imagery showed an eye like feature, Conson had intensified into a typhoon. The JMA also reported at 1800 UTC that Conson had reached its initial 10-minute peak sustained windspeeds of 110 km/h (75 mph) despite predicting that it would intensify into a typhoon before making landfall in the Philippines. Early on July 13 the JTWC also reported that Conson had reached its initial 1-minute peak sustained windspeeds of 130 km/h (70 mph).

Throughout northern Vietnam, officials urged residents living along coastal areas to evacuate inland. Fishermen were also told to return to port in order to avoid being caught in dangerous swells in the typhoon. A total of 18,371 people heeded the warnings and evacuated and 40,337 ships returned. The Department of Water Resources stated that there was a likelihood that the storm would produce significant flooding across the region as rainfall between 100 and 200 mm (3.9 and 7.9 in) was anticipated. Farmers were told to construct dikes around their crops in attempts to protect their fields. A storm surge between of 3 to 5 m (9.8 to 16.4 ft) was forecast to impact the coast.[12]

Within the Philippines, 102 people died and 46 people are listed as missing. Damage is estimated at 378 million 2010 PHP (8.17 million 2010 USD).[9]

When Conson made landfall in Quezon province at 11:00 pm (PST)/ 15:00 (UTC), power supply in Metro Manila, including 35 hit provinces in Luzon, went out. Telecommunications were also lost. Trees were uprooted, poles were strewn on the streets and rooftops were blown off. Classes from primary to college were suspended until July 14. NAIA recorded wind gusts of 95 km/h. At regional airports, air traffic officials canceled 29 international and local flights due to dangerous flying conditions brought about by the storm.[13] Elementary and pre-school classes for Metro Manila and affected provinces in Luzon canceled its classes before the afternoon of July 13.[14][15] 15 Philippine Airlines flights from different airports were canceled due to heavy rain, gusty winds and near zero visibility. Roughly 500 passengers in Bicol and Quezon Province were stranded at their respective ports as the coast guard declared that ships may not depart due to high waves and heavy rains.[16] Areas that had public storm signal warnings experienced high winds and torrential rains.[16] Off the coast of Pandan, 20 fishermen went missing after their boats capsized amidst rough seas produced by the storm. By July 13, only one person had been rescued while the 19 others still remain missing. Near Bagamanoc, 11 other fishermen went missing due to similar incidents.[13]

On July 16, Typhoon Conson brushed the southern coast of Hainan Province, resulting in substantial damage. Along the coast, winds were recorded up to 126 km/h (78 mph).[17] At least two people were killed in the country after being struck by advertisement billboards in separate incidents.[18] Trees also fell across the island causing significant structural damage on homes and businesses.[19] The storm produced moderate to heavy rainfall across Hainan,[20] peaking at 182.9 mm (7.20 in) in Sanya along the southern coastline.[21] The storm also ended a long dry spell affecting the island, leading to some seeing the storm as a positive event for the province.[20] According to preliminary damage assessments, 544 homes were destroyed, 7,000 hectares (17,300 acres) of crops were lost and 572,326 people were affected.[22] Monetary losses from the typhoon were estimated at ¥500 million ($73.8 million USD),[23] ¥120 million ($17.7 million USD) of which was sustained Sanya alone.[19][21][22]

Most of Sanya was left without power during Conson's passage as trees struck power lines and power poles were downed by high winds. Roads across the area became impassable due to fallen billboards, some reaching 5 m (16 ft) in height, and trees. The sudden onset of destructive winds caught many people off-guard, stranding them along roadways. Within 15 minutes, the local police in the city were overwhelmed with calls from residents.[24] Further away from the storm's center, moderate to heavy rainfall was reported in association with Conson's outer bands in Guangdong. There, rainfall was measured up to 68 mm (2.7 in).[25]

Off the coast of Vietnam, at least 13 fishermen were listed as missing after being caught in large swells produced by the storm.[26] In Hai Phong City, 97 homes were damaged or destroyed and three people were injured. Along the coast of the Cát Hải District, Conson's storm surge inundated low-lying areas. As the storm moved inland, strong winds caused widespread power outages in Quảng Ninh Province. Roads and bridges in the area remained open; however, several motorcyclists were forced to stop driving and sit along the bridges as high winds made travel extremely dangerous. In the Tĩnh Gia District, one tourist drowned after being washed away by large swells at a beach house. Initial reports indicated that two others drowned; however, these were later proven incorrect.[27] After the storm passed through, a second person, a child, was confirmed to have died during the storm.[28] By the morning of July 18, 11 people were reported missing across the country.[29] Heavy rains were reported throughout the northern half of the country, with more than 127 mm (5.0 in) of rain falling in Nam Dinh.[30] By July 24, reports throughout the country stated that 13 people were missing as a result of the storm.[31] Binh Bridge, a mayor bridge of Hai Phong was hit by three ships which were set loose by the typhoon. One ship, the Vinashin Orient, was stuck under the deck, damage it. The bridge was closed, await damage assessment.[32]

After moving inland, the remnants of Conson brought heavy rainfall to parts of northern Laos.[30]

Conson was poorly forecasted by PAGASA. From July 12 to 13, Conson was forecasted to hit Aurora and Isabela provinces. But, at 11 pm PST (1500 UTC) on July 13 PAGASA changed its forecast from Isabela-Aurora landfall, to Quezon province landfall. However, residents living in those areas were not advised that the typhoon would hit their area and they also were not informed that public storm signal number 2 was raised. With this, severe damage ensued in the said areas. Later that same day, President Benigno Aquino III reprimanded PAGASA for failing to predict that Conson would pass over Manila.[33]

Following the substantial damage in Sanya City, 1,000 police officers were deployed to keep order and ensure operations went smoothly. Fire and rescue teams relocated 200 people who were trapped in destroyed homes across the area.[34]

Three vessels of the Vietnamese navy were sent to the region near the Paracel Islands to search for the trace of 27 fishermen which had been missing since July 17. 58 other fishermen were reported to have been previously rescued.[35]